HRP20090247A2 - Autonomous base station for mobile telephony network - Google Patents

Abstract

Thus, by heating the device (4) in an underground room (2), and by supplying fresh ambient air through the pipes (3), a buoyancy current is achieved which drives the buoyancy turbine connected to the power generator (8). The cables (7) supply electricity to the battery (5) and thus close the circuit. The ejector (9) serves to amplify the buoyancy effect, especially when winds occur. The ribs (10) on the tubes also serve to increase buoyancy, conveying heat to the earth. Fire dampers (12) have the purpose of extinguishing fires and regulating drafts and / or buoyancy.

Description

The field to which the invention relates

No mobile operator can satisfy users if it does not build a sufficient number of base stations. Thus, base stations are placed in the shape of a honeycomb, so mobile phones are called "cell phones" in some countries.

The basic elements of a base station are an antenna pole on which GSM or some other type of antennas are installed, and a room, mostly in the form of a free-standing container, in which the equipment necessary for operation is located.

Currently, around 3,000 base stations for mobile telephony have been built in the Republic of Croatia, and another 2,000 will need to be built by all operators.

Technical problem

Electronic equipment heats up during its operation and thus causes the appearance of heat dissipation. For this reason, each such device has a built-in fan so that the heat can pass from the device to the surrounding air. That surrounding air in the space is heated, and it must also be cooled, that is, if the ambient temperature is lower than the temperature in the space, this heat is transferred to the surrounding air until the equalization temperature is reached.

The heat generated by the operation of the device is either expelled into the environment or the air is additionally cooled by the devices installed in the room.

Throwing "waste heat" into the environment is a common way of transferring the heat generated by the devices located in the base station container (device cooling).

Base stations are mostly equipped with split systems for cooling the installed equipment.

Such units have a cooling effect of about 5 kW and more, while the electrical power required for such a cooling effect is 3.5 kW and more. This is one of the reasons why every base station needs a strong power source. This is achieved by power supply from the power grid if it is available or by a diesel electric generator.

Of course, the operation of each base station, i.e. device placed in a container, requires permanent 24-hour operation. In the event of a power outage, back-up is included in the form of battery units that can supply basic needs (not air conditioning) for approx. 2-4 hours.

Losses due to power outages can be large because the outage of one base station means a loss for both the user, that is, the impossibility of connecting to the mobile network and for the operator, because there is no connection establishment and thus no call billing.

The heat dissipation of the installed equipment in the base station containers is at least 3.5 kW if it is the equipment of one operator. The containers in which the equipment is placed are exposed to weather influences and thus to additional heating in the summer months.

This is the biggest problem in the operation of the base station and huge resources are invested in cooling the container. Because without cooling devices, the operation of the base station would not be possible.

It should be noted that the complete equipment installed in the container of the base station needs approx. 1 kW for its operation. It is known that the tendency of the development of electronic equipment is to consume less energy, but unfortunately it still generates a lot of heat during operation.

Presentation of the essence of the invention

The autonomous base station of mobile telephony consists of two parts:

Antenna column

Underground rooms

Antenna pole

The antenna pole is designed as a tube with a taper towards the top, in the form of a truncated cone. The pipe segments are 6 m in size and are joined by flange joints. In this way, various column heights can be obtained; 12, 18, .....42, 60 meters.

All installations, waveguides and electricity pass through the pipe. lines, and GSM antennas, microwave antennas, etc. are usually placed on top.

A steel pipe is not new in the production of antenna poles, but it is necessary for this principle of operation.

Only in a vertical pipe is it possible to achieve buoyancy due to the difference in air temperatures.

An invention can be made, that is, the pipe can be installed on an existing or new grid column, and then the pipe is installed through the center of the column or around the perimeter.

Underground room

The underground room is a concrete room that also serves as the foundation of the antenna pole, and when calculating the dimensions, thickness of the walls, brand of concrete, it is necessary to know the load on the pole, the influence of wind and the like.

The dimensions of the room may be different, depending on the above and the need to accommodate the equipment of the Autonomous Base Station of mobile telephony.

Power calculation

As mentioned before, the heat dissipation of the installed equipment creates a heat flow of 3500W.

The temperature of the devices during operation is around 45° C, that is, if heat was not taken from the devices, then the temperature would rise above 55° C and more, which is the upper limit of endurance.

Above the underground concrete room is a pipe, that is, an antenna pole whose diameter in the lower part is 1.2 meters.

The supply of fresh, cold air is made possible by pipes that pass through the ground so that the air is cooled even in warm periods. Namely, those pipes are made with additional ribs, so that the outside air, in the warm months, enters the room cooled down, therefore, it would transfer the heat to the surrounding earth.

In the case of the autonomous base station of mobile telephony implemented in this way, we have the case of a heat station created as a result of the dissipation of the device and the chimney represented by the antenna pole in the form of a pipe.

That's why the calculation comes down to calculating the buoyancy of heated air.

The calculation was made for ideal conditions; outside temperature 0 ° C, in the room 45 ° C, so buoyancy is achieved due to the temperature difference between the outside air and the one in the underground room.

Static buoyancy is calculated:

U=h (ρz - ρd ) g

h = 40 meters, the height of the antenna pole

ρz = 1.35 kg/m³, air density in winter conditions and at altitude

ρd =1.25 Tz/Td kg/ m³, air density in the room

g = acceleration due to gravity, 9.81 m/sec²

Tz, the temperature of the outside air, in winter conditions 273 K

Td, the temperature in room a is caused by the heat dissipation of the device, 318 K

So it is:

U= 40 (1.35-1.073) 9.81 = 108.7 Pa

So, the buoyancy of warm air achieves a pressure of 108.7 Pascal

To calculate the power obtained by buoyancy, you need to know the speed of the warm air flow:

v² = U/ρ

here ρ is the air density 1.35 kg/m³

so it follows:

v² = 108.7/1.35 = 80.51

v = 8.973 m/sec

When the speed of the air at lift is known, then the power can be calculated from the following formula:

P = A · ρ · v³

A = d²· 3.14/4, the area of the internal section of the pipe, with a diameter of 1.2 meters, this amounts to 1.13 m²

P = 1.13·1.35·8.973³ = 1002 W

So, under the mentioned conditions, 1 kW of power can be obtained from the wind turbine generator.

A short description of the drawing with an explanation of terms

Figure 1 shows a cross-section of the complete plant of the Autonomous Base Station for mobile telephony, on which the following are numerically indicated:

1. Antenna pole in the form of a tube

2. Underground concrete room for housing the equipment necessary for the operation of the Autonomous Base Station of mobile telephony

3. Pipes for supplying fresh outside air

4. Radio and other devices Autonomous base stations of mobile telephony

5. Battery station

6. Opening with a door for the entrance to the room

7. Electrical cables that connect the generator to the batteries

8. Lift turbine with generator

9. Ejector with steering wheel

10. Ribs on the pipes that are used to transmit the heat of the outside air to the surrounding earth

11. GSM antennas

12. Anti-fire and control dampers at the same time

A detailed description of at least one way of realizing the invention

Start of work

In order for the system to work independently, it must have an impulse. The impulse is given by the battery 5 in such a way that it supplies electricity to the devices 4. In doing so, the devices heat up and due to the draft that occurs due to the supply of fresh air through the pipes 3, buoyancy is created towards the antenna pole 1, and the devices start to cool down at the same time.

The buoyant current of air moves towards the buoyant turbine 8, which rotates and thus produces electricity with the help of a generator, which in turn feeds the batteries via cables 7.

As can be seen from the calculation, a power gain of 1 kW is possible under the specified conditions.

If such conditions are not met, we cannot get the calculated power.

In order to obtain a certain vertical speed of the air flow through the antenna pole and thus the necessary power even in bad weather conditions, an ejector with a guide 9 is installed on the open top of the pole 1.

The purpose of the ejector is that when the wind occurs, there is an increase in pressure at the entrance to the ejector and a drop in pressure in the throat of the ejector.

By decreasing the pressure in the throat, a better outflow of the air current from the lower part of the antenna pole is achieved, thus canceling out the negative effects due to air friction and higher ambient temperature.

The buoyancy turbine located in the antenna pole can therefore convert the power obtained by the buoyancy of warm air with the help of a generator into electrical energy that is used for the operation of radio devices 4 Autonomous base stations of mobile telephony.

Of course, the radio devices located in the underground room are not directly powered, but the electricity thus obtained is used to charge the accumulators located in the underground room, and then the devices are powered from them.

Permanent drive

As long as the devices 4 are in operation and heated, a continuous supply of electricity is possible, so by heating the devices, air lift is obtained and thus a certain power on the blades of the lift turbine.

Fire dampers 12 are used to regulate the air flow in order to regulate the buoyancy and air temperature in the underground room.

Regulation is achieved by measuring the pressure or measuring the speed of the air current.

By completely closing the flaps, the operation of the generator stops, but this also causes the device to overheat.

In the case of an increase in the outside air temperature, the air supply pipes 3 are equipped with cooling fins, so the warm current of the outside air transfers the heat to the ground via the fins 10. The cooling surface of the fins 10, the length and diameter of the pipe depend on the depth of the pipe installation and the microclimate of a certain area.

In the same way, and it has already been said, the ejector with the router 9 will help to achieve sufficient buoyancy necessary for proper operation in bad weather conditions.

Additional effects of the idea:

The fire dampers are connected to the fire alarm control panel located in the room, which switches to the alarm state via automatic fire detectors in the event of a fire, thereby closing all the fire dampers.

By closing the fire dampers, the amount of oxygen in the air of the underground room decreases and the burning stops.

There is no need to install a protective fence around the antenna pole because there is no distribution cabinet or live cables, which in certain cases can cause death.

No cooling device should be installed to cool the radio equipment.

The floor plan area of the occupied land for construction is smaller.

If the GSM antennas of several operators are placed on the antenna pole, which has become a legal obligation, then the radio equipment of all operators is placed in an underground room, which is more convenient because more equipment generates more heat, which increases the buoyancy and thus the power required for the production of electricity.

The underground concrete room has an unlimited lifetime.

In the event that the antenna pole is of the grid type, then a plastic or steel tube with a lifting turbine is also placed along the longitudinal axis.

If the container with the equipment was left on the surface next to the antenna pole, then it would be possible to direct the warm air towards the antenna pole with the pipe system, and the supply of fresh air for cooling could be delivered again through the ground, in the same way as mentioned before.

So the principle remains the same

Financial result:

It is important to note that only current costs are included in the budget, and the amount of installation of refrigeration equipment as well as its maintenance is neglected.

If the construction of an additional 200 Autonomous base stations for mobile telephony in the territory of the Republic of Croatia by one operator is foreseen, then the savings due to the autonomy of the system would be on an annual level:

200 autonomous base stations of mobile telephony x 12h x 365 days x 1 kW x HRK 0.9/kW = HRK 788,400.00.00

The autonomy of the system is calculated on a 12-hour working day because it is considered that ideal conditions will not prevail throughout the year.

And the savings due to the unnecessary installation of split cooling systems, which consume an average of 3.5 kW of electricity for a predictable 12-hour day of operation:

12 hours x 365 days x 3.5 kW x HRK 0.9 x 200 autonomous mobile telephony base stations = HRK 2,759,400.00

So it's yearly:

788,400.00 + 2,759,400 = HRK 3,547,800.00/year

As information about the consumption of all base stations in the Republic of Croatia:

3000 base stations x 5.5kW x 12 h x 365 days = 72,227,000 kWh x 0.9 kn/kW = 65,004,000 kn/year

Claims (7)

1. An autonomous base station for mobile telephony, characterized by the fact that it consists of an antenna pole in the form of a pipe (1), an underground concrete room (2), a fresh air supply pipe (3), radio devices (4), a battery station (5 ). 2. Autonomous base station of mobile telephony according to claim 1, characterized by the fact that it consists of an underground room (2) and thus enables the accommodation of radio equipment (4) that does not need to be cooled by cooling devices, as they are cooled by air supplied through pipes (3) equipped with ribs (10) and at the same time the operation of the device (4) heats the air in the room (2), which enables the creation of air buoyancy in the antenna pole (1) which drives the buoyancy turbine with the generator (8) and thus produces electricity, which makes the station independent of other necessary sources of electricity supply. 3. The station according to claim 2, characterized by the fact that it also has an ejector installed on the top of the pole (1) with a directional rudder (9), which serves to create a negative pressure in the upper part of the pole (1) in the event of wind, which is necessary in order to facilitated the flow of warm air from the underground room (2) towards the top of the column (1), and it is the rudder on the ejector (9) that directs the ejector always in the direction of the wind, and this results in the wind pressure at the entrance to the ejector (9) creating an increase in the air speed in the throat the same, and thus there is a drop in pressure in the upper part of the antenna pole (1), which enables better buoyancy even in adverse external conditions and cancels out the damage caused by air friction. 4. The station according to claim 1, characterized by the fact that the air for cooling the radio equipment (4) is supplied through pipes (3) equipped with ribs (10) which are used to cool the warm air from the outside environment in unfavorable weather conditions in such a way that it passes over the surface the ribs (10) transfer the heat of the warm outside air to the surrounding earth and thereby achieve that the air entering the underground room (2) is always at the same temperature, which ensures a uniform flow of air towards the lifting turbine (8) regardless of weather conditions. 5. The station according to claim 1, characterized by the fact that it is equipped with fire dampers (12) which are used to close the radio equipment (4) in the event of a fire and therefore prevent the flow of fresh air into the room (2), thereby reducing the amount of oxygen in the room ( 2) due to burning and thus putting out the fire. 6. The station according to claim 1, indicated by the fact that it is equipped with fire dampers (12) which further serve to regulate the draft and thus the speed of the air flow in the column (1) itself, and optimal working conditions are always achieved with such automatic regulation. 7. The station according to claim 1, characterized by the fact that it consists of a pole (1), the height of which also depends on the obtained electrical energy, and by selecting a certain height, the obtained power required for powering radio devices (4) can be determined in advance, because the height of the pole is directly proportional to the obtained power.